"At this time, we are unaware of any misuse of the information contained in the software on the laptop," she said, adding that Fidelity has been monitoring activity in the affected HP accounts.

"We have taken steps to implement extra security processes requiring additional authentication for access to those HP accounts, as well as other measures to prevent unauthorized use," she said without elaborating.

Following the theft, Fidelity contacted the three principal credit-reporting bureaus to advise them of the situation, and it has arranged for affected HP employees to enroll in a free credit-monitoring service.

The compromise highlights the dangers of storing confidential data on mobile devices without adequate security controls, said Robert Egner, a vice president at security vendor Pointsec Mobile Technologies Inc. in Mokena, Illinois.

Such systems need additional controls to protect against accidental data exposure when mobile devices are lost or stolen, he said.